The present invention relates to a hydropneumatic accumulator having a bag and an acoustic filter.
An accumulator comprises a body generally made from steel, a bag generally made from elastomer and placed in said body and a transfer tube. A liquid is contained in the body. The accumulator makes it possible at any time to place this liquid under pressure for performing a given task. For example, it is used for machine tool locking devices, for braking or uncoupling devices for vehicles or public works machines, etc. It is also used on a nuclear reactor for injecting boron-containing water into the primary circuit in the case of an incident.
The invention relates to a hydropneumatic accumulator having a bag, comprising a body having an inlet and an outlet, a bag made from a flexible, deformable material insulating the inlet from the outlet, a liquid contained in the bag on the outlet side, a tube containing openings on its side wall and closed at its end and a diffuser assembly mounted around the tube.
Hydropneumatic accumulators of this type are known from GB-A No. 1 118 129 and U.S. Pat. No. 3,161,208. In such accumulators, the diffuser assembly is constituted by a helical spring, whose wire has a circular, triangular or rectangular cross-section. A plug is fixed to the free end of the spring.
These devices suffer from the disadvantage of clogging risks. There is also a risk of the bag fracturing.
To obviate these disadvantages, FR-A No. 1 408 181 provides hydropneumatic accumulators having a transfer tube constituted by a diffuserholder tube having holes and fritted bronze diffusers mounted with elastomer inserts on the diffuser-holder tube. However, a construction of this type suffers from serious disadvantages. Thus, the gas, e.g. compressed air, injected into the bag contains oil droplets. Under the action of pressure, these droplets are finely atomized in the gas, in the manner in which this takes place in a diesel injector and can give rise to an explosive or "auto-igniting" mixture. This mixture can explode under the effect of the pressure increase and can lead to the accumulator body or its pipes exploding.